Telephone system



W. T. BOOTH.

TELEPHONE SYSTEM.

APPLICATION FILED JULY 9,1911.

Patented Dec. 16,1919.

/n ven for: Vl f/fiam 7. 500772. y

, UNITED STATES PATENT OFFICE.

WILLIAM T. BOOTH, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTERNELECTRIC COMPANY, INCGEPORATED, OF NEW' YORK, N. Y., A CORPORATION OFNEW YORK.

TELEPEEGN E SYSTEM.

Specification of Letters Patent.

Patented Dec. 16, 1919.

Application filed. July 9, 1917. Serial No. 179,473.

' East Orange, in the county of Essex and State of New Jersey, haveinvented certain new and useful Improvements in Telephone Systems, ofwhich the foll wing is a full, clear, concise, and exact description.

7 This invention relates totelephone sys tems, and the principal objectof the invention is to pro-videa simple and efiicient arrangement ofcircuits and apparatus to effeet communication between the differentstations of a t lephone system and to accomplish this, electromagneticmeans are provided to control the connection of the telephone set of acallingstation with the line of a called station; the electromagneticmeans serving to do away with the necessity of releasing any callingkeys which might be depressed at the called station before said stationcould answer and also serving as an impedance coil through which talkingcurrent is supplied to the system.

This and other features of the invention may be readily understood byreference to the accompanying drawing wherein the in vention is shown asapplied to an intercommunicating telephone system. Three stations areillustrated, each having lines extending to the other stations, althoughohviously a greater number of stations may be similarly connected ifdesired.

In making the call, the calling party removes his recei er anddepressesthe calling key of the desired station to its lowermostposition. Si naling current is thereby supplied to operate the signal atthe called station. Current from both the sig naling and talkingbatteries is also supplied. to the right-hand windin of a relay at thecalling station which hereupon pulls up. The calling key is then allowedto return to its intermediate position, which removes the signalingbattery from the circuit, and, the relay at the calling station beingup, supplies talking current through its windings to the telephone setof the calling station; this relay thus serving as a retardation coil.The relay also cooperates with the depressed calling key to placetalking battery on the lines individual to hecalled station, and theremoval of the receiver at the called sta tion by the party ans e i g,br es the thereof across the lines individual thereto to place theparties in communication irrespective of whether any calling keys are inintermediate position at the called stae tion or not. On completion ofconversation, the parties hang up, whereupon the relay at the callingstation falls off without the calling key, however, being released fromits intermediate position. On depressing another calling key in making asubsequent call, the first key is automatically released in the usualmanner.

A somewhat more detailed-description of the operation will serve to moreclearly explain the invention; and, for this purpose, assume thatstation A wishes to call station B. The receiver at A would be removedbutwould have no effect other than to bridge the telephone set ofstation A across the lines 1 and 1 individual thereto; similar lines 2,2 and 3, 3 being provided for stations B and C, respectively. The partyat station A would then depress calling key K individual to station B.This key in common with the other calling keys K K and K is designed sothat when depressed as far as it will go it will bring the fourth springcontact into engagement with the lowermost spring and also engage thecenter spring thereof with the fourth spring and also with a busbar l.The keys remain in the lowermost position only so long as they aremanually held there by the personcalling and return to an intermediateposition in which they are held by the usual locking plate 5, as soon aspressure on the calling button is relieved. In intermediate positiononly the first and second and third and fourth springs, respectively, ofthe keys are en gaged. The operation of any key in callingreleases anyother key which may be locked in intermediate position, although it isnot necessary that keys which may be locked in position at a calledstation be released to obtain connection with the calling line toprevent interference by other parties,

although this has been generally necessary heretofore in systems of thiskind.

The lousbar 4 is connected by a conductor 6 to a lead wire 7 extendingto one side of a signaling battery 8 common to the system;

posite poles of the different batteries being connected thereto. On fulldepression of the key K a circuit is completed to operate a signal 11 atstation B; this circuit extending from battery 8, lead wire 7, busbar4:,

. third spring of key K conductor 12, line wire 2, conductor 13,hookswitch let and lower contact thereof at station B, conductor 15,signal 11, conductor 16, and lead wire 9 to the other side of signalingbattery 8. The signal 11 interrupts its own circuit and operates only solong as the key K is held in its fully depressed position.

Another circuit is also completed at this time to energize theright-hand winding of relay 17 at station A to pull up the armaturesthereof; this circuit extending from lower side of battery 8, lead wire7, conductor 6, busbar at, third, fourth and fifth springs of key Kconductors 18, 19 and 20 right-hand winding of relay l7, conductor 21and lead wire 9 to the other side of ringing battery 8. Relay 17 onpulling up serves to complete a holding circuit for itself; this circuitbeing the same as that just traced to the fourth spring of the key Kfrom whence it extends by conductors 22, 23 and 24, right-hand armatureand upper front contact of relay 17, through the right-hand windingthereof to conductor 21, and lead wire 9, to the positive side ofbattery 8. The attraction of the armatures of relay 17 also completes acircuit through both windings of this relay; this circuit extending fromthe negative side of talking battery 10, lead wire 9, conductor 21,right-hand winding of relay 17, upper inner contact and ri ht-handarmature to lower inner contact thereof, conductors 25 and 26,transmitter, receiver and upper contact of hookswitch of station A,conductor 27, lower inner contact and left-hand armature of relay 17,upper inner contact thereof, left-hand winding of relay 17 and conductor28 to lead wire 29, and positive side of talking battery 10.

The holding circuit previously traced from ringing battery through theright-hand winding of the relay would practically neutralize the effectof current from the battery 10 through this winding, but the lefthandwinding is actively energized at this time and serves to hold thearmatures attracted.

The key K would now be released to intermediate position, whereupon thecircuit from the signaling battery 8 through the right-hand winding ofthe relay 17 is opened at the busbar 41; leaving both windings, however,energized by talking battery 10. The relay windings under theseconditions are interposed between talking battery and the telephone setof station A and serve as an impedance or retardation coil for currentsupplied thereto. Talking current is thus supplied to station A and therelay ,1? being energized, battery also placed on the line wires 2 and 2of station B through the right-hand armature of relay 17 and fourth andthird springs of key K and the lefthand armature of relay 17 and secondand first springs of key K respectively, so that on the party at stationB removing his receiver, a talking circuit is completed in parallel withstation A. This parallel circuit begins at the upper front contact andlefthand armature of relay 17, and extends over conductors 30, 31 and32, second and'first spring of key K at station A, conductor 33, linewire 2, conductors 31, 35, transmitter and receiver of station B, uppercontactand hookswitch 1 1, conductor 13, line wire 2, e011- ductor 12,third and fourth springs of key K at station A, and conductors 22, 23and 24 to right-hand armature and upper front contact of relay 17.

As previously stated, a calling key which has been depressed is notordinarily released until another is operated so that although station Bmight be idle, when station A at tempted to secure a connection thereto,a calling key at station B would be in intermediate position. Assumethat key K at station B was in this position and that a fourth station(not shown) was connected with station C. Under these conditions talkingcurrent would be present on the line wires 3, 3, and while it would passthe engaged springs of the key K at station B, it would not interferewith the conversation between stations A and B, as the circuit betweenthese stations and the line 3, 3 is open at the armatures of the relay38 at station B, sincethis relay is not operated when ation B is called.Interference by station C is thereby automatically prevented withoutnecessitating the provision and manual opera-tion of a home button atthe called station in answering to release any calling button which maybe depressed thereat. The relay arrangement in the present case thusinsures greater simplicity of operation than was possible with systemsgenerally in use heretofore, which require the provision and manualoperation of a home button to prevent interference between two or morepairs of connected stations.

The parties at stations A and B are thus free to converse in the usualmanner and on termination of the conversation, both parties would hangup their receivers, whereupon the relay 17 at station A would bedeenergized, restoring the system to normal w'thout, however releasingthe key Y this fact, however, being immaterial as key K at station A canremain in intermediate position until another calling key is operatedthereat without interfering with the opera-.

tion of the system as previously explained.

lVhat is claimed is: 1. In a telephone system, a plurality of pairs ofindividual conductors, a plurality of telephone-sets each permanentlyassociated with a difierent pair of said conductors, a relay having awinding, selective switching means individual to one of said telephonesets to cooperate with said relay tov connect one of said telephone setswith another pair of said conductors, and a source of current for saidsystem; the winding of said relay also serving as an impedance means forcurrent supplied therethrough to the winding of said one of said relaysalso serving as an impedance means for current supplied therethrough toits respective tele phone set.

3. In a telephone system, a plurality of pairs of individual conductors,a plurality of telephone sets each permanently associated with adifferent pair of said conductors, a relay having a winding andindividual "to each of said telephone sets, selective switching meansindividual to each of said tele phone sets to cooperate with one of saidre lays to connect the telephone set of said relay with another pair ofsaid conductors; the winding of said one of said relays also serving asan impedance means for current supplied therethrough to the telephoneset associated with said other pair of conductors.

4. In a telephone system, a plurality of pairs of individual conductors,a plurality of telephone sets each permanently associated with adifferent pair of said conductors, a relay having a winding andindividual to each of said telephone sets, selective switching meansindividual to each of said telephone sets to cooperate with one of saidrelays to connect the telephone set of said relay with another pair ofsaid' conductors; the winding of said one of said relays also serving asan impedance means for current suppliedtherethrough to a plurality ofconnected telephone sets.

5. In a telephone system, a plurality of pairs of individual conductors,a plurality of telephone sets each permanently associated with adifferent pair of said conductors, a relay having a winding andindividual to each of said telephone sets, selective switching meansindividual to each of said telephone sets to cooperate with one of saidrelays to connect the telephone set of said relay with another pair ofsaid conductors;

the winding of said one of said relays also serving as an impedancemeans for current supplied therethrough to its telephone set and to thetelephone setassociated with said other pair of conductors. V A

6. In a telephone system, a plurality of line circuits, a telephone setassociated with each of said circuits, a relay individual to each ofsaid circuits to connect the line circuit thereof to another of saidcircuits and having a plurality of windings, switching means associatedwith each of said telephone sets to coeperate with one of the relaysindi-' vidual to line circuits which it is desired to associate togetherto connect such circuits, and a source of .current for said system; awinding of the relay cooperating with said switching means beinginterposed between each of the terminals of the source of current andthe connected line circuits to serve. as an impedance means for currentsupplied to said connected line circuits.

7. In a telephone system, a plurality of line circuits, a telephone setassociated withv each of said circuits, a relay individual to each ofsaid circuitsto connect the line circuit thereof to another of said linecircuits and having a plurality of windings, switching means associatedwith eachof said tele phone sets to cooperate with the relay thereof toconnect the line circuit thereof to another of said line circuits, and asource of current for said system; a winding of said relay beinginterposed between each of the terminals of the source of current andthe connected line circuits to serve as an impedance means for currentsupplied to the line circuits so connected. I V

8. In a telephone system, a plurality of line circuits, a telephone setassociated with each of said circuits, a relay having a plu' 105 ralityof windings, switching means individual to said telephone sets adapted.to co operate with said relay to connect two of said line circuitstogether, and a source of current for said system; a winding of said 110relay being interposed between each of the terminals of the source ofcurrent and the line circuits of the system to serve as an im- V pedancemeans for current supplied to said line circuits.

9. In a telephone system, a plurality of line circuits, a telephone setassociated with each of said circuits, a relay individual to each ofsaid circuits. each relay hav ing a plurality of windings, switching 120means individual to said telephone sets adapted to cooperate with saidrelays to connect two of said line circuits together. and a source ofcurrent for said'systemz one winding of said relays being interposed 125between each of the terminals of the source of current and the linecircuit to which the respective relay is individual to serve as animpedence means for current supplied to such-line circuit I a r 10. In atelephone system, a plurality of line circuits, a telephone setassociated with each of said circuits, a relay individual to each ofsaid circuits, each relay having a plurality of windings, switchingmeans in dividual to said telephone sets to cooperate with said relaysto connect two 01 said line circuits together, and a source of cur--rent for said system; the operation of said with each of said circuits,a relay individual to each of said circuits, each relay havmg aplurality of windings, switching means associated with each of saidtelephone sets to cooperate with the relay individualto the line circuitthereof to connect such circuit to another of said line circuits, and asource of current normally dissociated from said line circuits andconnected to the different line circuits by the operation of the relayindividual to the particular line circuit; said relays each having awinding thereof interposed between each of the terminals of the sourceof current and the line circuit to which the respective relay isindividual whereby said relays on operation serve as an impedance meansfor current supplied to the respective line circuit.

12. In a telephone system, a plurality of line circuits, a telephone setassociated with each of said circuits, a relay having a plurality ofwindings, switching means cooperating with said relay to connect two ofsaid line circuits together, and a source of current normallydissociated from said line circuits and connected thereto by theoperation of said relay; a, winding of said relay being interposedbetween each of the terminals of the source of current and said linecircuits, whereby said relay on operation serves as an impedance meansfor current supplied to said line circuits.

13. In a telephone system, a plurality of lin circuits, a telephone setassociated with each of said circuits, relays individual to each of saidline circuits, each relay having a. plurality of windings, switchingmeans cooperating with said relays to connect two of said line circuitstogether, and a source of current normally dissociated from said linecircuits and connected thereto by the operation of said relays; awinding of each of said relays being interposed between each of theterminals of the source or current and its respective lme c1rcu1t,whereby each.

of said relays on operation serves as an impedance means for currentsupplied to its respective line circuit.

14%. In a telephone system, a plurality of pairs of individualconductors, a plurality of telephone sets each permanently associatedwith a different pair of said conductors, a relay having a winding,selective switching means individual toone of said tele-,

phone sets to cooperate directly with said relay to connect one of saidtelephone sets with another pair of said conductors, and a source ofcurrent for said system; the winding of said relay also serving as animpedance means for current supplied therethrough to one of saidconnected telephone sets 15. In a telephone system, a plurality of pairsof individual conductors, a plurality of telephone sets each permanentlyassoci ated with a different pair of said conductors, a relay having awinding and individual to each of said telephone 1 sets, selectiveswitching means individual to each of said telephone sets to cooperatedirectly with one of said relays to connect the telephone set of saidrelay with another pair of said conductors; the winding of said one ofsaid relays also serving as an impedance means for current suppliedtherethrough to its respective telephone set.

16. In a telephone system, a plurality of pairs of individualconductors, a plurality of telephone sets each permanently associatedwith a difierent pair of said conductors, a relay having a winding andindividual to each of said telephone sets, selective switching meansindividual to each of said telephone sets to cotiperate directly withone of said relays to connect the telephone set of said relay withanother pair of said conductors; the winding of said one of said relaysalso serving as an impedance means for current supplied therethrough tothe telephone set associated with said other pair of conductors.

17. In a telephone system, a plurality of pairs of individualconductors, a plurality of telephone sets each permanently associatedwith a different pair of said conductors, a relay having a winding andindividual to each of said telephone sets, selective switching meansindividual to each of said telephone sets to cooperate directly with oneof said relays to connect the telephone set of said relay with anotherpair of said conduc tors; the winding of said one of said relays alsoserving as an impedance means for current supplied therethrough to aplurality of connected telephone sets.

18. In a telephone system, a plurality of pairs of individualconductors, a plurality of telephone sets each permanently associatedwith a different pair or" said conductors, a relay having a winding, andindividual to each of said telephone sets, selective switching meansindividual to each of said telephone sets to cooperate directly with oneof said relays to connect the telephone set of said relay with anotherpair of said conductors; the winding of said one of said relays alsoserving as an impedance means for current supplied therethrough to itstelephone set and to the telephone set associated with said other pairof conductors.

19. In a telephone system, a plurality of line circuits, a telephone setassociated with each of said circuits, a relay individual to each ofsaid circuits to connect the line circuit thereof to another of saidcircuits and having a plurality of windings, switching means associatedwith each of said telephone sets to cooperatev directly with one of therelays individual to line circuits which it is desired to associatetogether to connect such circuits, and a source of current for saidsystem; a winding of the relay cooperating with said switching meansbeing interposed between each of the terminals of the source of currentand the connected line circuits to serve as an impedance means forcurrent supplied to said connected line circuits.

20. In a telephone system, a plurality of line circuits, a telephone setassociated with each of said circuits, a relay having a plurality ofwindings, switching means individual to said telephone sets adapted tocooperate directly with said relay to connect two of said line circuitstogether, and a source of current for said system; a winding of saidrelay being interposed between each of the terminals of the source ofcurrent and the line circuits of the system to serve as an impedancemeans for current supplied to said line circuits.

21. In a telephone system, a plurality of line circuits, a plurality oftelephone sets, a relay having a winding individual to each set toconnect its associated set with one of the line circuits, a source ofcurrent normally connected to one of the telephone sets when such set isin use through a winding of its respective relay, a second source ofcurrent, and means cooperating with the second source of current foroperating such relay to connect its respective set with one of the linecircuits.

In witness whereof I hereunto subscribe my name this 5th day of July, A.D. 1917.

WILLIAM T. BOOTH. I

